Current methods of synthesizing trinitrotoluene (TNT) involve successive mixed-acid nitrations of the petrochemical toluene (Milligan, B., “Isomer Distribution in Mixed-Acid Nitration of Toluene. Evidence for Mass-Transfer Effects on Selectivity” Ind Eng Chem Fundam, 25(4), 783-789 (1986). During this process, some undesired nitration isomers occur (α-, β, and γ-trinitrotoluene) as well as incomplete nitration products (2,4- and 2,6-dinitrotoluene). These unwanted isomers are removed by sellite (sodium sulfite) washings. Isomers with nitro groups ortho to one another react with the sulfite generating ionic, water-soluble products. These washes have a characteristic red color, hence the name ‘red water’. These washings are highly toxic and very expensive to destroy (incinerate). Because of this ‘red water’ problem, there are no North American plants that will produce TNT. Currently, all U.S. needs for TNT are supplied from overseas sources where environmental standards are mild or non-existent.
A report by Hill and Torrey explain the chemistry and analogous condensation of nitromalondialdehyde (Hill, H. B., Torrey, J. Jr., “CXV. On Nitromalonic Aldehyde” Amer Chem J. 22, 89-110 (1899). However, the report does not teach nor suggest the use of dinitro-compounds to make trinitro aromatics (TNT).
U.S. Pat. No. 5,946,638 issued on Aug. 31, 1999 to Jayasuriya, et al., and U.S. Pat. No. 5,977,418 issued on Nov. 2, 1999 are based on a process for regaining the nitration of toluene in the presence of zeolites. The products from the nitration process in these patents do not include trinitrotoluene (TNT) aromatics. Although the zeolites help to make the nitration reaction more regioselective, there still remain small percentages of unwanted isomers that must be removed (i.e. sellite washings) This present invention is completely different from the above patents, there is not nitration of an aromatic ring, hence no regioisomer issues. The invention described here is a novel ring forming reaction of two nitro components to form an aromatic ring in a completely regiospecific manner.
There exists a need in the art for an environmentally friendly alternative to the current manufacturing process for the high explosive 2,4,6-trinitrotoluene (TNT) which does not produce the highly toxic nitration isomers and products responsible for “red water” waste.